Change the case of readme file
Move changelog to HISTORY.md
Remove PHP4 compatible code

WordPress now requires at least PHP v5.2.4 or above
Add compatibility for Easy Digital Downloads plugin

EDD plugin filters the title to adds some HTML to it for some
customization. When the title is used as the default tweet text, twitter
doesn't like having HTML in twitter text.

This commit checks if EDD is installed and removes the filter briefly if
found.

Fix #5
Bump up version for v3.0.2 for release
Regenerate pot file for v3.0.2